Table 4. Summary of recommendations for micronutrient requirements and supplementation pre-conception, during pregnancy and lactation post bariatric surgery (15,38-42).
| Nutrient | RDI for adult non-pregnant women* | RDI for adult pregnant women* | RDI for adult lactating women* | Suggested RDI for pregnant women post bariatric surgery** | Recommended supplementation for pregnant women post-bariatric surgery | Reason for increase demand | Maternal nutrient intake/absorption affects milk concentration |
|---|---|---|---|---|---|---|---|
| Vitamin B12 | 2.4 μg/d | 2.6 μg/d | 2.8 μg/d | 300–500 μg/d | Supplementation of vitamin B12 as required to normalise serum levels. Dose dependent on route: 350–500 μg daily orally or sublingually; 1,000 μg monthly intramuscular or subcutaneously | Related to reduced absorption following surgery | Yes |
| Iron | 18 mg/d | 27 mg/d | 9 mg/d | 45–60 mg/d | Supplementation of at least 45 mg/d of iron is recommended (either contained in a multivitamin or as a separate iron supplement); absorption is enhanced by vitamin C and is impaired by; calcium, acid-reducing medications, and foods containing phytates and polyphenols | Related to reduced absorption following surgery, and increased fetal and maternal demand | No |
| Folate | 400 μg/d (a 400 μg/d folic acid supplement is routinely recommended if trying to conceive) | 600 μg/d (a 400 μg/d folic acid supplement is routinely recommended) | 500 μg/d | 800– 1,000 μg/d |
Supplementation of at least 800 μg/d of folate is recommended (either contained in a multivitamin or as a separate folic acid supplement); commence supplementation one month prior to conception and continue during pregnancy; 5 mg/d folic acid is recommended if BMI >30 kg/m2; History of neural tube defects; Inflammatory bowel disease; Pre-existing T2DM | Related to reduced absorption following surgery and for prevention of neural tube defects | Severe maternal deficiency results in lower breastmilk concentrations |
| Iodine | 150 μg/d (a 150 μg/d supplement is routinely recommended if trying to conceive) | 220 μg/d (a 150 μg/d supplement is routinely recommended) | 270 μg/d (a 150 μg/d supplement is routinely recommended) | 220 μg/d | Supplementation of at least 150 μg/d of iodine is recommended (likely contained in multivitamin) | Increased fetal demand for brain and nervous system development |
Yes |
| Calcium | 1,000 mg/d | 1,000 mg/d | 1,000 mg/d | 1,200– 1,500 mg/d |
Supplementation of 1,200–1,500 mg/d of calcium is recommended, with dose adjusted for dietary intake; calcium citrate supplements may have better bioavailability, than calcium carbonate; avoid taking with iron supplement, due to impaired absorption | Related to reduced absorption following surgery | No |
| Vitamin D*** | 5 μg/d | 5 μg/d | 5 μg/d | 75 μg/d (3,000 IU/d) | Supplementation of 3,000 IU/d of Vitamin D is recommended, and dose titrated according to biochemistry until within normal range | Related to reduced absorption following surgery | Not at usual maternal intakes (some experimental evidence that high levels of supplement increase breastmilk content) |
| Vitamin A (retinol equivalents) | 700 μg/d | 800 μg/d | 1,100 μg/d | 1,500–3,000 μg/d (5,000–10,000 IU/d) | Supplementation of all fat-soluble vitamins is recommended of at least: 1,500 μg/d RE of vitamin A, 7 mg/d of vitamin E, and 60 μg/d of vitamin K (contained in some multivitamins); note pregnancy multivitamins may not contain vitamin A. Vitamin A supplementation is recommended in the form of beta-carotene, not retinol or retinyl ester forms as this may have teratogenic effects | Related to reduced absorption following surgery | Only if mother’s stores are depleted |
| Vitamin E*** | 7 mg/d | 7 mg/d | 11 mg/d | 7–15 mg/d | Supplementation can increase breastmilk content | ||
| Vitamin K*** | 60 μg/d | 60 μg/d | 60 μg/d | 60–120 μg/d | Supplementation can increase breastmilk content | ||
| Thiamin | 1.1 mg/d | 1.4 mg/d | 1.4 mg/d | At least 12 mg/d | Supplementation of at least 12 mg/d of thiamin is recommended (likely contained in multivitamin); supplementation of an additional 200–300 mg/d if prolonged vomiting is experienced (i.e., hyperemesis gravidarum) | Related to reduced absorption following surgery. Minimal increase during pregnancy for utilization in energy production for growth of maternal and fetal tissue | Yes |
| Zinc | 8 mg/d | 11 mg/d | 12 mg/d | 11–22 mg/d | Supplementation of at least 11 mg/d of zinc and 1.3 mg/d of copper is recommended (likely contained in multivitamin); to minimise risk of copper deficiency, it is prudent to maintain ratio of 8–12 mg zinc: 1 mg copper. Avoid taking zinc and copper supplementation together where possible, due to impaired absorption | Related to reduced absorption following surgery, and increased maternal and fetal demand due to growing tissue | No |
| Copper*** | 1.2 mg/d | 1.3 mg/d | 1.5 mg/d | 1.3–2 mg/d | Related to reduced absorption following surgery. Minimal evidence on requirements in pregnancy, small additional allowance provided to cover increased tissue demand | No evidence available |
*RDI, recommended daily intake, as per Australian Nutrient Reference Values (without bariatric surgery); **, suggested RDI was based on existing evidence for nutrient requirements in pregnancy and post bariatric surgery micronutrient supplementation recommendations (15,38-42). Unless otherwise specified, this RDI can be met through dietary intake and/or supplementation. In some cases, blanket supplementation is recommended and has been specified above. Where a range is specified, clinical judgement should be used considering surgery type, dietary intake and biochemical value. ***AI, adequate intake, as per Australian Nutrient Reference Values (without bariatric surgery); used when RDI cannot be determine and is the average daily nutrient intake level based on observed or experimentally-determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate (38). Adapted from McGuire (39) and used with permission.